Heretofore, as a method for producing a three-dimensional molded object with a fused deposition modeling method, for example, the following Patent Document 1 discloses a method for producing a minute three-dimensional medical structure. In this method, while the movements of a minute syringe and molding stage facing the syringe are controlled based on the shape data of a three-dimensional structure, a minute medical three-dimensional structure is formed by repeating a step of discharging a thinning thermally fused product made of a biodegradable resin from a syringe nozzle. Further, the following Patent Document 2 discloses a method for forming a three-dimensional structure requiring no filament-like material. In the method, a thermally melted polymer material is extruded from a nozzle using a gas pressurization dispenser, and the discharge position of the nozzle at this time is controlled.
However, the method described in Patent Document 1 decreases the volume of the resin stored in the syringe, which causes a problem that a large molded object cannot be produced. The method of Patent Document 2 makes it necessary to prepare nitrogen or carbon dioxide as a gas inactive against the polymer material in order to suppress the generation of an oxide caused by thermal decomposition, and makes it difficult to control the discharge of the resin since the fused resin is extruded by gas pressurization, which is disadvantageously apt to cause resin dripping from the tip of the nozzle.
Furthermore, in the production of a three-dimensional molded object using a three-dimensional printer which has been widely used in these days, PLA (polylactic acid) provided in a filament form or a filament of ABS (acrylonitrile-butadiene-styrene) is used as a material to be laminated. This filament is pressurized by a feed motor, and extruded from the tip of the nozzle via the heated block, to form a molded object. However, the conventional three-dimensional printer using such a filament is less likely to control the sending speed of the filament, and is apt to cause the clogging of the filament. The nozzle clogging disadvantageously stops a forming step and limits the material suitable for the filament, which makes it impossible to use pellets (granular materials) made of various commercially available materials.